Malik Jackson, standing in a tube chamber that leaves only his head exposed, stares blankly as liquid nitrogen gas swirls around him. There are no cameras, though. And the scene has become part of a weekly routine for the Broncos defensive end and many of his teammates, including linebacker Von Miller, cornerbacks Aqib Talib and Kayvon Webster, and safeties Omar Bolden, T.J. Ward and Darian Stewart.

The whole-body cryotherapy craze took off in 2011, when the Dallas Mavericks, the second-oldest team in the NBA that season, credited the treatment for helping them win their first league championship.

Professional soccer and rugby players had long been using it in Europe and Asia, where it was first developed in 1978 to help treat arthritis and inflammatory diseases. But the use by professional athletes in the U.S. was in its infancy. Now LeBron James and the Cleveland Cavaliers turn to it regularly. Major League Baseball players have used it. Floyd Mayweather incorporated it in his training before his fight with Manny Pacquiao. Olympic sprinters Usain Bolt and Justin Gatlin often take mobile cryotherapy units with them to races.

And the Broncos have joined the growing trend.

Call it an ice bath on steroids.

For 2½ to 3 minutes, the players stand in a full-body chamber wearing only shorts, gloves and socks as liquid nitrogen gas engulfs their limbs and torso at temperatures of minus-250 to minus-300 degrees Fahrenheit.

The treatment claims to rely on deception, lowering the temperature of the skin by 30 to 50 degrees to trick the brain into thinking the entire body is freezing. The mind game leads to a fight-or-flight response and the release of endorphins, the body’s natural painkillers, to help reduce soreness and inflammation.

Unlike traditional ice baths that require painful submersion in ice and water for about 15 minutes, cryotherapy sessions are said to be painless and more effective.

“We’ll actually use it with a lot of the guys Sunday morning before they go to the stadium, so about three hours before kickoff we’ll go through and use the cryotherapy on them because it cleans out any inflammation, soreness that they have, but it also kind of dumps endorphins back into the body,” said Dr. Ryan Tuchscherer, a chiropractor and the co-founder of Cherry Creek Spine and Sport Clinic. “It really gets them amped up and ready to go, versus the old, traditional way of doing an ice bath or an ice tank.”

This year, Tuchscherer, whose clinic is one of about 150 in the U.S. to house the $75,000 whole-body cryotherapy units, has worked with primarily defensive players from the Broncos, seeing them regularly during the season.

Some players use them for maintenance, after game days and practices. Others use them for recovery from specific injuries.

“With Aqib and his ankle injury, we’ll use that to try to get it to speed up so we can get them back on the field quicker,” Tuchscherer said. “It’s cutting the recovery time down, usually in half from what it usually would be. You’re seeing it a lot with the professional athletes.”

But the research on whole-body cryotherapy, which is not Food and Drug Administration-approved, has offered mixed results.

A 2011 study in France found a reduction of inflammation in participants who entered the chamber before and after a run on a treadmill that was designed to create muscle damage and soreness. The study indicated that the runners’ reduced inflammation could cut back on their recovery time.

But a 2015 review by Joseph Costello, a senior research associate at the University of Portsmouth in England, reported there was “insufficient evidence to determine whether whole-body cryotherapy reduces self-reported muscle soreness, or improves subjective recovery, after exercise” compared with rest or no cryotherapy in adult males.

“Is it 100 percent? It’s not,” Tuchscherer said.

But the Broncos, like many other professional athletes, believe in the benefits of whole-body cryotherapy.

“The professionals do it because that’s their job,” Tuchscherer said. “That’s how they make their money, keeping their body healthy.”

After watching Air Force kick the CU Buffaloes’ tail, not to mention their undefeated record, into the wild, blue yonder, here’s a legitimate question: How in the world is the Pac-12 recognized as a Power Five football conference?